Cardiac resynchronization therapy in heart failure patients with atrial fibrillation

Comparison of His-Purkinje Conduction System Pacing with Atrial-Ventricular Node Ablation and Pharmacotherapy in HFpEF Patients with Recurrent Persistent Atrial Fibrillation (HPP-AF study)

BACKGROUND

There is currently no particularly effective strategy for patients with persistent atrial fibrillation accompanying heart failure with preserved ejection fraction (HFpEF), especially with recurrent atrial fibrillation after ablation. In this study, we will evaluate a new treatment strategy for patients with persistent atrial fibrillation who had at least two attempts (≧2 times) of radio-frequency catheter ablation but experienced recurrence, and physiologic conduction was reconstructed after atrioventricular node ablation or drug therapy, to control the patient's ventricular rate to maintain a regular heart rhythm, which is called His-Purkinje conduction system pacing (HPCSP) with atrioventricular node ablation.

METHODS AND RESULTS

This investigator-initiated, multicenter prospective randomized controlled trial aimed to recruit 296 randomized HFpEF patients with recurrent atrial fibrillation. All the enrolled patients were randomly assigned to the pacing group or the drug treatment group. The primary endpoint is differences in cardiovascular events and clinical composite endpoints (all-cause mortality) between patients in the HPCSP and drug-treated groups. Secondary endpoints included heart failure hospitalization, exercise capacity assessed by cardiopulmonary exercise tests, quality of life, echocardiogram parameters, 6-minute walk distance, NT-ProBNP, daily patient activity levels, and heart failure management report recorded by the CIED. It is planned to compete recruitment by the end of 2023 and report in 2025.

CONCLUSIONS

The study aims to determine whether His-Purkinje conduction system pacing with atrioventricular node ablation can better improve patients' symptoms and quality of life, postpone the progression of heart failure, and reduce the rate of rehospitalization and mortality of patients with heart failure.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR1900027723, URL: http://www.chictr.org.cn/edit.aspx?pid=46128&htm=4.

Conduction system pacing: promoting the physiology to prevent heart failure

Cardiac conduction system pacing provides physiological ventricular activation by directly stimulating the conduction system. This review describes the two types of conduction system pacing: His bundle pacing (HBP) and left bundle area pacing (LBAP). The most significant advantage of HB pacing is that it can provide a regular, narrow QRS; however, the disadvantages are challenging implantation and a high risk of re-intervention due to lead dislodgement and the development of high pacing threshold. LBAP provides optimum physiological activation of the left ventricle by engaging the left bundle/fascicular fibers. LBAP is more physiological than traditional RV apical pacing and could be an attractive alternative to conventional cardiac resynchronization therapy (CRT). The advantages of LBAP are a relatively more straightforward implantation technique than HBP, better lead stability and pacing thresholds. HBP and LBAP are more physiological than right ventricular pacing and may be used instead of conventional pacemakers. Both HBP and LBBP are being investigated as alternatives to conventional CRT.

HOT CRT-The Effective Combination of Conventional Cardiac Resynchronization and His Bundle Pacing

Background and Objectives: Cardiac Resynchronization Therapy (CRT) has, besides its benefits, various limitations. For instance, atrial fibrillation (AF) has a huge impact on the therapy efficacy. It usually reduces the overall BiV pacing percentage and leads, inevitably, to lack of fusion beats. In many patients with heart failure that could benefit from resynchronization, the QRS morphology is often IVCD and atypical, or non-LBBB, which further diminishes the CRT response. In those cases, we established His pacing combined with LV pacing as a feasible option to reduce the impact of AF on the CRT response and regain partially physiological ventricular activation to improve the electromechanical sequence. Materials and Methods: We implanted two patients with AF, HF, EF < 35%, NYHA II-III and QRS > 150 ms with CRT-D systems modified to HOT-CRT and observed their clinical, ECG and echocardiographic improvements over a follow-up period of three months. Results: In both patients we observed improvements of the initial parameters. We were able to shorten the QRS duration to approx. 120 ms, improve NYHA functional class, increase the EF by approximately 12% and distinctly reduce mitral regurgitation. Conclusion: Since the conventional CRT reaches its limits within this specific patient group, we need to consider alternative pacing sites and the effective combination of them. Our results and respectively other studies that are also mentioned in the current guidelines, support the feasibility of HOT-CRT in the above mentioned patient group.

Impact of cardiac resynchronisation therapy on burden of hospitalisations and survival: a retrospective observational study in the Northern Region of New Zealand

OBJECTIVE

Cardiac resynchronisation therapy (CRT) devices have been shown to improve heart failure (HF) symptoms, survival and improve quality of life (QoL). We evaluated the overall impact of CRT on recurrent hospitalisations and survival in real-world patients with HF.

DESIGN

Retrospective observational study.

SETTING

Northern region of New Zealand.

PARTICIPANTS

Patients with HF who underwent CRT device implantation in between 2008 and 2014 were followed up for 1 year.

INTERVENTIONS

CRT.

PRIMARY AND SECONDARY OUTCOMES MEASURED

Survival, all-cause hospitalisations, length of stay, from which days alive and out of hospital (DAOH) were calculated.

RESULTS

177patients were included, of whom eight died (4.5%) within 1 year of follow-up. Pre-CRT implantation, 83% of all patients had been hospitalised for a total 248 hospitalisation events. Following CRT, 47 patients (27%) were readmitted to hospital within 1 year (total of 98 admissions; p<0.01 compared with pre-device implant). Length of hospital stay was significantly shorter than in the year prior to CRT implantation at a median of 4 (IQR 2-6) vs 7 (IQR 3.5-10.5) days (p=0.03). An increase in the median number of DAOH was observed from 362 (IQR 355-364) to 365 (IQR 364-365) (p<0.01) after CRT implant. The improvement in DAOH was seen regardless of gender and type of CRT devices. Greater DAOH was also seen in those with non-ischaemic cardiomyopathy and Caucasians.

CONCLUSION

After CRT implant, patients with HF have greater DAOH with reduction of total hospitalisation and fewer hospital days. These results support CRT devices use as a treatment option for appropriate HF patients. DAOH represents an easily measured, patient-centred endpoint that may reflect effectiveness of interventions in future CRT studies.

Triple-site pacing for cardiac resynchronization in permanent atrial fibrillation: follow-up results from a prospective observational study

Aims

Cardiac Resynchronization Therapy (CRT) is associated with a particularly high non-response rate in patients with atrial fibrillation (AF). We aimed to assess the effectiveness of triple-site (Tri-V) pacing CRT in this population.

Methods and results

Prospective observational study of patients with permanent AF who underwent CRT implantation with an additional right ventricle lead in the outflow tract septal wall. After implantation, programming mode (Tri-V or biventricular pacing) was selected based on cardiac output determination. Patients were classified as responders if NYHA class was reduced by at least one level and echocardiographic ejection fraction (EF) increased ≥ 10%, and as super-responders if in NYHA class I and EF ≥ 50%. Forty patients (93% male, mean age 72 ± 10 years) were included. Thirty-three were programmed in Tri-V. The following results pertain to this subgroup. At baseline, 58% were in NYHA class III and 36% NYHA class II. At 1 year follow-up, Minnesota QoL score was reduced (36 ± 23 vs. 8 ± 6; P = 0.001) and the 6MWT distance improved (384 ± 120 m to 462 ± 87 m, P = 0.003). Mean EF increased (26% ± 8 vs. 39 ± 10; P < 0.001 at 6 months and 41 ± 10; P < 0.001 at 12 months). Responder rate was 59% at 6 months and 79% at 12 months. Super-responder rate was 9% at 6 months and 16% at 12 months. One year survival free from heart failure hospitalization was 87.9%.

Conclusion

Tri-V CRT yielded higher response and super-response rates than usually reported for CRT in patients with permanent AF using clinical and remodeling criteria.

Prophylactic implantable cardioverter defibrillator in heart failure: the growing evidence for all or Primum non nocere for some?

Heart failure (HF) is a common health problem and has reached epidemic in many western countries. Despite the current era of HF treatment, the risk of sudden cardiac death (SCD) in HF remains significant. Implantable cardioverter defibrillator (ICD) support has been shown to reduce the risk of SCD in patients with HF and impaired left ventricular function. Prophylactic ICD implantation in HF patients seems a logical step to reduce mortality through a reduction in SCD. However, ICD implantation is an invasive procedure, and both short- and long-term complications can occur. This needs to be carefully considered when evaluating the risk-benefit ratio of ICD implantation for individual patients. As the severity of HF increases, the proportion of SCD compared with HF-related deaths decreases. The challenge lies in identifying patients with HF who are at significant risk of SCD and who would most benefit from an ICD in addition to other anti-arrhythmic strategies. This review offers insight on the applicability and practicability of ICD for this growing population.

His Bundle Pacing: A New Frontier in the Treatment of Heart Failure

Biventricular pacing has revolutionised the treatment of heart failure in patients with sinus rhythm and left bundle branch block; however, left ventricular-lead placement is not always technically possible. Furthermore, biventricular pacing does not fully normalise ventricular activation and, therefore, the ventricular resynchronisation is imperfect. Right ventricular pacing for bradycardia may cause or worsen heart failure in some patients by causing dyssynchronous ventricular activation. His bundle pacing activates the ventricles via the native His-Purkinje system, resulting in true physiological pacing, and, therefore, is a promising alternate site for pacing in bradycardia and traditional CRT indications in cases where it can overcome left bundle branch block. Furthermore, it may open up new indications for pacing therapy in heart failure, such as targeting patients with PR prolongation, but a narrow QRS duration. In this article we explore the physiology, technology and potential roles of His bundle pacing in the prevention and treatment of heart failure.

R/S Ratio Variability in Lead V1 Observed between Selected Four 1-Minute ECG Fragments of 24-Hour ECG as a Predictor of Incomplete Resynchronization during Full 24-Hour ECG: Pilot Study

BACKGROUND

About 30% of patients do not have an effective cardiac resynchronization therapy (CRT). Routine assessment of CRT by devices interrogation (DI) is not entirely reliable. Additional information provide detailed QRS analysis in 24-hour ECG, however it is time-consuming. The aim of the study was the assessment of R/S ratio variability in lead V1 between selected fragments of 24-hour ECG as a predictor of incomplete biventricular pacing (BIVP) during full 24-hour ECG.

METHODS

The 12-lead 24-hour ECGs of 43 patients with sinus rhythm were studied. During 24-hour ECG the 6-minute walk test (6MWT) was performed. The CRT was assessed by analyzing DI and full 24-hour ECG and four 1-minute fragments of these ECG recordings: during the minimum and the maximum heart rate and at the 1st and last minute of 6MWT.

RESULTS

During DI the effective (>95%) BIVP was present in 36 patients (83.7%). Analysis of full 24-hour ECG confirmed appropriate BIVP in 31 patients (72%) and suspected incomplete BIVP (≤95%) in 12 patients (28%). In 9/12 patients the R/S ratio variability in lead V1 was visible between selected ECG fragments of 24-hour ECG. These results were not associated with the results of DI but were significantly associated with full 24-hour analysis of QRS.

CONCLUSIONS

R/S variability in lead V1 between selected fragments of 24-hour ECG can be considered a predictor of potentially incomplete BIVP confirmed by further complete 24-hour ECG analysis in patients with appropriate pacing reported during DI.

The postimplantation electrocardiogram predicts clinical response to cardiac resynchronization therapy

BACKGROUND

Biventricular (BiV) pacing for cardiac resynchronization therapy (CRT) is intended to improve left ventricular function by coordinating systolic activity of the septum and free walls. Optimal resynchronization should be manifested by 12-lead electrocardiogram (ECG) patterns consistent with resynchronized activation, a tall (≥4 mm) R wave in V1, and predominant negative deflection in lead I (RV1SI). We investigated whether the presence or absence of RV1SI predicts heart failure outcomes within 1 year of CRT implant.

METHODS

Two independent physicians reviewed the paced ECG of 213 patients post-CRT device implantation with disputes resolved by a third reviewer. The primary end points of all-cause death, unplanned hospitalization, left ventricular assist device implant, or transplant within a 1-year follow-up were blindly adjudicated according to standard definitions. Groups were compared via Kaplan-Meier estimates and Cox proportional hazards models to determine association with event-free survival.

RESULTS

Among CRT patients postimplantation, 56 (26.3%) exhibited the RV1SI pattern on ECG. Patients with the RV1SI pattern were significantly less likely to achieve the primary end point as compared to patients without the RV1SI pattern (33.9% vs 52.2%; Log Rank P = 0.022). This difference was driven by a significantly lower risk for unplanned hospitalization among patients with the RV1SI pattern (hazard ratio = 0.510; confidence interval [0.298, 0.876]). The predictive value remained after adjustment for potential confounders (P = 0.004).

CONCLUSIONS

The 12-lead ECG postimplantation predicts clinical outcomes of BiV pacing. Such prediction may be useful in predicting the need for alternative or advanced heart failure therapies. Further study into ECG patterns may help to prospectively guide CRT.

Effects of atrioventricular nodal ablation on permanent atrial fibrillation patients with cardiac resynchronization therapy: a systematic review and meta-analysis

Cardiac resynchronization therapy (CRT) is a well-established therapy for patients with heart failure (HF) and wide QRS configuration, especially for those in sinus rhythm. However, for those with permanent AF, atrioventricular nodal (AVN) ablation use remains under debate. Our objective was to evaluate clinical outcomes and mortality of AVN ablation in HF patients with permanent AF receiving CRT. Electronic publication database and reference lists through October 1, 2013 were searched. Observational cohort studies comparing CRT patients with AF who received either AVN ablation or medical therapy were selected. Outcomes included mortality, CRT nonresponse, changes in left ventricular remodeling, and functional outcomes, such as New York Heart Association (NYHA) functional class, quality of life, and 6-minute hall walk distance. Of 1641 reports identified, 13 studies with 1256 patients were included. Among patients with permanent AF and insufficient biventricular pacing (< 90%), those who had undergone AVN ablation compared to those who did not had numerically lower all-cause mortality (risk ratio [RR]: 0.63, 95% confidence interval [CI]: 0.42 to 0.96, P = 0.03) and significantly lower nonresponse to CRT (RR: 0.41, 95% CI: 0.31 to 0.54, P < 0.00001). Furthermore, AVN ablation was not associated with additional improvements on left ventricular ejection fraction, NYHA functional class, 6-minute hall walking distance, and quality of life. In patients with permanent AF undergoing CRT, AVN ablation tended to reduce mortality potentially and improved clinical response when it was applied to patients with inadequate biventricular pacing (< 90%). Randomized controlled trials are needed to further address the efficacy of AVN ablation among this population.

Use of Cardiac Resynchronisation Therapy - Change of Clinical Settings

Current guidelines recommend cardiac resynchronisation therapy (CRT) for patients with severe left ventricular dysfunction (left ventricular ejection fraction [LVEF] ≤35 %), QRS duration of ≥120-150 ms (Class IA and IB indications) on surface electrocardiogram (ECG) and New York Heart Association (NYHA) class III or IV heart failure (HF) symptoms. Ongoing studies aim to expand the use of CRT in patients with asymptomatic or minimal symptoms left ventricular dysfunction. There have been studies that have shown benefit of CRT extended to this group of patients. There have also been different implications of the role of CRT in patients with atrial fibrillation (AF), patients with narrow QRS duration or with right bundle branch block (RBBB) on surface ECG, as well as patients with end-stage renal failure on dialysis therapy. This article aims to review the current body of evidence of expanding use of CRT in these populations.

Battery longevity in cardiac resynchronization therapy implantable cardioverter defibrillators

AIMS

Cardiac resynchronization therapy (CRT) implantable cardioverter defibrillators (ICDs) deliver high burden ventricular pacing to heart failure patients, which has a significant effect on battery longevity. The aim of this study was to investigate whether battery longevity is comparable for CRT-ICDs from different manufacturers in a contemporary cohort of patients.

METHODS AND RESULTS

All the CRT-ICDs implanted at our institution from 1 January 2008 to 31 December 2010 were included in this analysis. Baseline demographic and clinical data were collected on all patients using the electronic medical record. Detailed device information was collected on all patients from scanned device printouts obtained during routine follow-up. The primary endpoint was device replacement for battery reaching the elective replacement indicator (ERI). A total of 646 patients (age 69 ± 13 years), implanted with CRT-ICDs (Boston Scientific 173, Medtronic 416, and St Jude Medical 57) were included in this analysis. During 2.7 ± 1.5 years follow-up, 113 (17%) devices had reached ERI (Boston scientific 4%, Medtronic 25%, and St Jude Medical 7%, P < 0.001). The 4-year survival rate of device battery was significantly worse for Medtronic devices compared with devices from other manufacturers (94% for Boston scientific, 67% for Medtronic, and 92% for St Jude Medical, P < 0.001). The difference in battery longevity by manufacturer was independent of pacing burden, lead parameters, and burden of ICD therapy.

CONCLUSION

There are significant discrepancies in CRT-ICD battery longevity by manufacturer. These data have important implications on clinical practice and patient outcomes.

Impact of atrial fibrillation on outcomes in heart failure

The prevalence of atrial fibrillation (AF) and heart failure increases with advancing age. It is estimated that the annual incidence of AF in the general heart failure population is approximately 5%, whereas as many as 40% of patients with advanced heart failure have AF. The goals of therapy in patients with heart failure and AF are symptom control and prevention of arterial thromboembolism. The adverse hemodynamic events of AF may lead to symptom deterioration and reduced exercise capacity. This review addresses the impact of AF on heart failure outcomes as they pertain to prognosis and management.

Role of Atrio-Ventricular Junction Ablation in Symptomatic Atrial Fibrillation for Optimization of Cardiac Resynchronization Therapy

Cardiac resynchronization (CRT) therapy is indicated in patients with at least mildly symptomatic heart failure, left ventricular ejection fraction ≤35% and wide QRS, and has been associated with decreased morbidity and mortality. Unfortunately, approximately 30% of the patients appropriately selected for therapy do not respond to CRT. Among the reasons for non-response, atrial fibrillation (AF) plays a prominent role. AF limits the degree of biventricular pacing during CRT, not only when the ventricular rate is fast and highly irregular, but also during periods of of relatively constant rate, by causing fusion and pseudo-fusion complexes. Importantly, achievement of nearly 100% biventricular pacing is necessary to derive benefit from CRT. A simple, albeit irreversible, method to maximize biventricular pacing in patients with AF who are otherwise eligible for CRT is atrioventricular junction (AVJ) ablation. In this review, we discuss the role of AVJ ablation in CRT optimization in patients with AF. The available evidence from observational non-randomized studies suggests that AVJ ablation in patients with AF qualifying for CRT may offer improvement in heart failure symptoms, better survival, and better cardiac function. In light of the inherent limitations of non-randomized studies, further randomized studies are needed to support this treatment option.

Cardiac Resynchronization Therapy in Patients with Atrial Fibrillation - Worth the Effort?

Congestive heart failure (CHF) and atrial fibrillation (AF) are two increasingly common conditions that predispose to each other and frequently coexist. Cardiac resynchronization therapy(CRT) has emerged as an important therapeutic modality for selected patients with end-stage CHF. However, despite the high prevalence of AF in patients eligible for CRT, almost all the randomized clinical trials that validated the benefit of resynchronization therapy excluded patients with preexisting AF. In this review, we examine the available evidence on the benefits and limitations of CRT in patients with AF and discuss recent data that narrowed the knowledge gap on this topic.

Left ventricular lead position for cardiac resynchronization: a comprehensive cinegraphic, echocardiographic, clinical, and survival analysis

AIMS

We sought to determine the clinical and survival outcomes of cardiac resynchronization therapy (CRT) associated with left ventricular (LV) lead location. The lateral left ventricle has been considered the optimal LV lead location for CRT.

METHODS AND RESULTS

Left ventricular lead cinegrams taken in 30° right and left anterior oblique views were evaluated in 457 recipients of CRT with a pacemaker or a defibrillator from 1 January 2002 to 31 December 2008 in this retrospective study. Left ventricular lead placement was prioritized at implantation into posterolateral (PL), anterolateral (AL), middle cardiac, and anterointerventricular coronary veins. Using echocardiographic LV 16-segment analysis, we grouped the leads as anterior, AL, PL, and posterior locations. New York Heart Association (NYHA) class and echocardiography were assessed before and after CRT. Clinical and survival outcomes after CRT were compared among the four LV lead locations.  Patient baseline demographic characteristics were similar among these four groups. Improvement in NYHA class was significantly greater in the AL (P= 0.04) and PL (P= 0.03) locations than in the anterior location. There was a tendency for greater improvement in LV ejection fraction among the AL (P= 0.11) and PL (P= 0.08) locations than the anterior location. Kaplan-Meier survival estimate at 4 years varied for location: AL, 72%; anterior, 48%; PL, 62%; and posterior, 72% (P= 0.003).

CONCLUSION

Cardiac resynchronization therapy recipients are profiting from all lead positions. However, LV lead placed in the AL and PL positions is more preferential for achieving optimal CRT benefit than leads placed in the anterior position.

Cardiac resynchronization therapy for patients with atrial fibrillation

Atrial fibrillation and chronic heart failure are two major and even growing cardiovascular conditions that often coexist. Cardiac resynchronization therapy is an important, device-based, non-pharmacological approach in a selected group of chronic heart failure patients that has been shown to improve left ventricular function and to reduce both morbidity and mortality in large randomized trials. The latest European and American guidelines have considered atrial fibrillation patients with heart failure eligible for cardiac resynchronization therapy. This review summarizes current literature concerning the following topics: prognostic relevance of atrial fibrillation in heart failure, effects of cardiac resynchronization therapy in atrial fibrillation, relevance and strategies of rhythm and rate control in this group of patients. Authors explain how atrial fibrillation may interfere with the delivery of adequate cardiac resynchronization therapy, how to reduce the burden of atrial tachyarrhythmias, and finally present a brief overview. Orv. Hetil., 2011, 152, 1757–1763.

Cardiac Resynchronization Therapy and Atrial Fibrillation

Cardiac resynchronization therapy (CRT) is an important advance for the treatment of end--stage heart failure (HF). About 15-50% of HF is complicated by atrial fibrillation (AF) and associated with worsened outcomes. Meta-analyses from observational studies suggest that patients with AF derive similar benefits to CRT as patients in sinus rhythm (SR). The presence of AF, however, may interfere with optimal delivery of CRT due to competition with biventricular (BiV) capture by conducted beats. Atrioventricular junction (AVJ) ablation with permanent pacing eliminates interference by conducted beats and provides complete BiV capture. Catheter ablation of AF is an alternative to antiarrhythmic drugs to maintain sinus rhythm in patients with AF and HF. Randomized trial comparing catheter ablation, AVJ ablation and pharmacologic therapy are needed.

[Treatment of progressive heart failure: pharmacotherapy, resynchronization (CRT), surgery]

The treatment of progressive and terminal heart failure follows the principle of causative therapy. Therefore, etiology and pathophysiology of the underlying disease and its hemodynamic conditions are indispensable. This applies to coronary artery disease, hypertension, valvular heart disease, the cardiomyopathies with and without inflammation, and microbial persistence similarly. The classic treatment algorithms both in heart failure with and without reduced ejection fraction are based on measures onloading the heart (angiotensin-converting enzyme inhibitors, angiotensin antagonists, beta-blockers, diuretics) and on antiarrhythmics and anticoagulation, when needed. Device therapy for cardiac resynchronization in left bundle branch block and permanent stimulation therapy may contribute to the hemodynamic benefit. ICD (implantable cardioverter defibrillator) therapy prevents sudden cardiac death, which is often associated with progressive heart failure. Heart transplantation and left ventricular assist devices are final options in the treatment repertoire of terminal heart failure.